CVE-2025-59980 is a medium-severity authentication bypass vulnerability identified in the FTP server of Juniper Networks Junos OS. The root cause lies in a primary weakness (CWE-305) where the FTP server permits login without password verification for users named 'ftp' or 'anonymous' if these accounts are configured and the FTP service is enabled. This flaw allows unauthenticated, remote attackers to gain limited read-write access to the home directory of these users on the device. The vulnerability affects multiple Junos OS versions: all versions before 22.4R3-S8, 23.2 versions before 23.2R2-S3, and 23.4 versions before 23.4R2. Exploitation requires no privileges or user interaction, and the attack vector is network-based, making it relatively easy to exploit in environments where FTP is enabled. The impact primarily affects confidentiality and integrity, as attackers can read and modify files within the accessible directory, potentially leading to information disclosure or unauthorized configuration changes. However, availability is not impacted. No public exploits have been reported yet, but the presence of this vulnerability in network infrastructure devices like Juniper routers and firewalls poses a significant risk if left unpatched. Juniper has not yet provided patch links, but affected organizations should monitor for updates and apply them promptly once available.

For European organizations, this vulnerability presents a risk of unauthorized access to critical network infrastructure devices running Junos OS with FTP enabled. Attackers could leverage this flaw to read sensitive configuration files or logs, potentially gaining insights into network topology or credentials. Limited write access could allow modification of files within the home directory, which might be leveraged for persistence or to disrupt device operation indirectly. Given Juniper's strong market presence in Europe, especially among telecom providers, ISPs, and large enterprises, exploitation could lead to data breaches, network disruptions, or facilitate further lateral movement within corporate networks. The lack of required authentication and user interaction lowers the barrier for attackers, increasing the likelihood of exploitation in poorly secured environments. While availability is not directly affected, the confidentiality and integrity impacts could have cascading effects on network security and compliance with European data protection regulations such as GDPR.

European organizations should immediately audit their Junos OS devices to identify versions affected by this vulnerability and verify if the FTP server is enabled along with the presence of 'ftp' or 'anonymous' user accounts. If FTP is not required, it should be disabled entirely to eliminate the attack surface. Where FTP is necessary, restrict access to trusted management networks and consider using more secure file transfer methods such as SFTP or SCP. Monitor device logs for any unauthorized FTP login attempts. Implement network segmentation and access controls to limit exposure of management interfaces. Stay informed on Juniper's official patches and apply updates promptly once released. Additionally, review and harden user account configurations to remove or disable default or anonymous accounts. Employ intrusion detection systems to alert on anomalous FTP activity. Finally, conduct regular security assessments and penetration tests focusing on network infrastructure devices to detect similar weaknesses proactively.